Pawan Dewangan

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Pawan Dewangan
Pawan Dewangan headshot.png
PhD Geophysics
PhD university Colorado School of Mines

Pawan Dewangan has been the lead author of five papers in Geophysics and four expanded abstracts, and a co-author on two more Geophysics papers and two expanded abstracts. In 2011, Pawan received the prestigious Young Scientist Award from the Indian National Science Academy. His method of inverting VSP data for the full stiffness tensor is particularly impressive; nine years after publication of that work, it remains the only proven approach for in-situ characterization of triclinic (the most general) anisotropy. Pawan made a number of other significant contributions during his graduate studies at CSM, including (1) development of the full-waveform version of the “PP+PS=SS” method; (2) application of the moveout-asymmetry attributes of PS-waves to parameter estimation in tilted transversely isotropic (TTI) media; (3) a physical-modeling study of PS-wave moveout inversion for TTI media; (4) physical modeling and analysis of P-wave attenuation anisotropy for TTI samples; and (5) development of velocity-independent layer stripping for P-waves and mode-converted data. In the relatively short time that he has been a scientist in the National Institute of Oceanography in India, Pawan has become a highly valued geophysicist in his home country.

Biography Citation for the J. Clarence Karcher Award 2012

Contributed by Ilya Tsvankin and Ken Larner

It is always rewarding to see your former students continually on an upward scientific trajectory and making the most of their experience in graduate school. Pawan Dewangan is a scientist who continues expanding the scope of his research contributions, which are most deservedly recognized with the J. Clarence Karcher Award.

Pawan came to the graduate program at the Colorado School of Mines (CSM) from the Indian Institute of Technology (IIT) and earned his PhD in 2005. Living up to our expectations based on his outstanding performance in master’s studies at IIT, he was such a standout at Mines that faculty treated him more as a colleague than a student.

As a member of the A(nisotropy)-Team at the Center for Wave Phenomena (CWP), Pawan was known for his broad knowledge and a meticulous, measured way of preparing and delivering his presentations. On one occasion, it took Pawan four A-Team seminars to fashion his talk because he wanted to explore every angle of the problem. Upon graduation, despite a number of more lucrative options available to him, Pawan returned to India, where he is now a scientist in the National Institute of Oceanography (NIO). Pawan already has had a remarkable 19 papers published in top-rated international and Indian geophysical and computer science journals (including several in Geophysics).

Much of his research during and immediately following his PhD studies was focused on processing and inversion of seismic data for anisotropic media. In particular, he devised inversion of multicomponent, multiazimuth, walkaway VSP data for the stiffness tensor – that’s the full tensor described by 21 stiffnesses, not the conventionally limited one for transversely isotropic or even orthorhombic media. Working with Vladimir Grechka, Pawan not only extended the slowness-polarization method of VSP inversion to arbitrarily anisotropic media, but also successfully applied the new technique to data from Vacuum Field in New Mexico. It remains a landmark case study, which demonstrated the feasibility of resolving the entire local stiffness tensor from properly designed VSP surveys without making restrictive a priori assumptions about symmetry.

Among other important developments made by Pawan in graduate school are the interferometric version of the “PP+PS=SS” method that operates with full waveforms, parameter estimation for tilted transversely isotropic media using multicomponent data, and velocity-independent layer stripping (VILS) of PP and PS reflection traveltimes. In particular, VILS helps overcome well-known stability problems in Dix-type nonhyperbolic moveout inversion and produce accurate estimates of interval anisotropy parameters. Recent case studies have proved the value of VILS in building interval orthorhombic velocity models (which are rapidly gaining in importance) from long-spread, wideazimuth reflection data. We would like to mention that another 2012 J. C. Karcher awardee, Jyoti Behura, has transformed VILS into a powerful tool for interval attenuation analysis by combining it with the spectral-ratio method. Pawan’s breadth in geophysics is best revealed in his papers published after he joined NIO in 2005. Topics include automatic interpretation of magnetic data using Euler deconvolution with nonlinear background, velocity and AVO analysis for detection of gas hydrates, finite-difference modeling of scattered hydrates in gas-hydrate exploration, rock-physics modeling of shallow marine sediments, offshore slumping/sliding attributable to gas/fluid movement, and studies of fault systems and thermal regimes.

Based primarily on his achievements since returning to India, in 2011 Pawan was recognized with the prestigious Indian National Science Academy (INSA) Young Scientist (YS) Award. Earlier, in 2009, he was selected as a Young Associate of the Indian Academy of Sciences in Bangalore.

Already in his young scientific career, Pawan has contributed broadly and prolifically to the exploration geophysical community at large, showing great strength in theory, computation, and interpretation—an impressive combination of the theoretical and the practical. He, moreover, relates in the most friendly and cooperative way with others and is sure to be a productive, highly valued researcher well into the future.